Greetings! I was wondering, does anyone have a dynamic solution for flexible vertex formats? For example, what if you have vertex position and uv, or vertex position and vertex normal or perhaps only vertex position or maybe vertex postioion with normal and uv? The thing is, how to load souch a file? for each fvf combination define own struct and read from file?! Is there a better way to do it? Thank you in advance!

I have defined my vertex formats like this:

enum eVertexFormat {
VF_POSITION = 1<<0, // vertex position 3 floats x,y,z
VF_NORMAL = 1<<1, // normal 3 floats x,y,z
VF_TEXCOORD2D_1 = 1<<2, // texcoord 1 2 floats u,v
VF_TEXCOORD2D_2 = 1<<3, // texcoord 2 2 floats u,v
VF_TEXCOORD2D_3 = 1<<4, // texcoord 3 2 floats u,v
// and so on
};

then a VertexBuffer class



so then I can create a VB with the vertexformat I like the order of the vertexdata is as the enum types is in the list: Position,Normal,TexCoord1,TexCoord2,... if the vertexformat of the VB doesn't have one of them then the next is there.

example:
This will create a vb with room for 3 vertex positions and their normals

CVertexBuffer *vb = new CVertexBuffer(VF_POSITION | VF_NORMAL, 3);

the data for that buffer will be x1,y1,z1,nx1,ny1,nz1,x2,y2,z2,nx2,ny2,nz2,...

This will create a vb with room for 3 vertex positions and their first uv coords

CVertexBuffer *vb = new CVertexBuffer(VF_POSITION | VF_TEXCOORD2D_1, 3);

the data for that buffer will be x1,y1,z1,u1,v1,x2,y2,z2,u2,v2,...

and if you want vertex position, normal and uv.

CVertexBuffer *vb = new CVertexBuffer(VF_POSITION | VF_NORMAL | VF_TEXCOORD2D_1, 3);

the data for that buffer will be x1,y1,z1,nx1,ny1,nz1,u1,v1,x2,y2,z2,nx2,ny2,nz2,u2,v2,...

And so on.

You could read through Yann L's famous Material/Shader posts. Lots of good info in there on ways to handle different shaders (and their data streams). You'd want to make a new thread if you have questions about that stuff, since you don't want to necro the old thread.

I use a system just like m4gnus for dynamic content. I VertexBufferWriter is instantiated with a specific vertex declaration ( dx9 style ) and then I iterate over the num vertices I need, and for each one fill in the data. The VertexBufferWriter knows where to put each member since it was passed the declaration (which knows the offset & stride of each component).

For static content that I might need to access I have a VertexBufferReader class which is templated so that I can do this:

struct StaticGeomVert{  Vertex3  vPosition;  Vertex3  vNormal;  Vertex2  vTexcoord0;};VertexBufferReader <StaticGeomVert*>vbReader( pModelObject, vertDecl );StaticGeomVert* pVertices = vbReader.LockVertices();for ( int i = 0 ; i < vbReader.GetNumVerts(); i++ ){  pVertices.vPosition.x += 1.0f;<br>}<br><br>vbReader.UnlockVertices();<br><br></pre><br><br>All of my models know their vertex format through a dictionary. I create, in the build pipeline, a dictionary of all used vertex declarations and then store a unique ID of that in the model. &#79;nce loaded I bind that ID to a pointer in the dictionary. This lowers our memory footprint and also makes the model header format fixed size. &#79;nly the dictionary needs to worry about the variable length nature of the vertex delcarations.<br><br>Hope that helps.<br><br>